Method of sealing the walls of oil-wells



w. E. NOLAN. METHOD OF-SEALING THE WALLS 0F OIL WELLS.

APPLICATION FILED APR. 3| 1920.

1,361,282. -Patented De@. 7,192.

y 6, 9% k @0 5 JWM/5gg@ ,l

ATTO R N EY g oil fields, may reach sixty or more feet, cap

'twelve hundred feet.

WILLIAM 'n NoLA-N, yer TULSA, oKLAIIoMA.

i iiyIE'rHoD or `similaire '.IIIL. WALLS or OIL-WELLS.

To all yw hom t may concern.'

Be it known that I, WILLIAM NOLAN,

a citizen of the United States, residing sat..

`Specification of-.Letters Patent.

Application led April "3, 19120. Serial No. 371,053.

Tulsa, in the county of Tulsa and State of Oklahoma, have invented :a new and useful Method of Sealing the Walls-of @il-'Wells of which the following is a specification.

This invention has reference to a method of sealing the Walls of oil wells :andits object is to `avoid thev necessity :of applying casing to the wells to prevent leakage, or seepage or cave-ins.

Ordinarily oil wells are drilled toa great depth and extend through strata which, at many points, may be of so unstable a nature that, unless artificially sustained., very readily cave in. Also the bore frequently traverses water-bearinff strata and such water must be excluded f wise, it would interfere with the production of the oil to the extent of entirely stopping it. c

In the ordinary procedure of drilling oil wells, which may reach three or four thousand or more lfeet in depth, cave-.ins and the inflow of water -is prevented by employing metal casing following thesinking of the drill into the earth. In such drilling, after 'rom the bore for, other-.

the surface llayer Yhas beenpierced, which layer in some localities, such as the Texas stone strata-1s encountered, such stone strata usually consisting of limestone, which 1s 1m- YPatented Dec. 7, 1920.-

lows Ya .smaller bore to accommodate Vfrom fifteen hundred to two thousandV feet of v casing'. followed by a smaller bore to accommodate twenty-five hundred to -three `thousand feet of 8 casing, and, finally, there is `drilled fa bore extending into the. yground from three to four thousand feet and taking 653 casing. The different `sizes of `casing ltelescoped one within the fother, all `reaching to the surface `.of the ground or kinto a cellar. .In :an oil Vwell of the depth of say l l4500.0 feet, which is not at all uncommonfin the llexas region, lthe total amount of "casing needed reaches nearly 11,1000 feet, sometimes less, but, in any event, ,representing :a length of casing vseveral 'times thatzof the depth A.of the well.

The cost of such a casing' together withl the work of drilling the well and installing the casing :and the losses .encounteredfrom various causes will make the `cost of slnking a 4,000 foot well reach in the neighborhood l of from eighty to one hundred thousand dolor duster, as they are termedl in the oil field.

pervious to both oil and gas, and to water.' x.

`As the -drillhole progresses past the cap stone strata it may pass through hundreds,

or even thousands Cof feet of shale, which.

would render the borepractically impossible were it not for the casing. -Underlying the shal`e is usually a layer of cap stone overlying the gas-bearing sandy-stone which, in turn, covers the oil-bearing sand stone, or sand, as it is commonly known.

In the ordinary procedure of boring anoil well several distinct casings are'employed. The well starts with an outer casing of, say,

fifteen to twenty inches in diameter, such casing being carried into the earth for, say,

four to five hundred feet. Thence follows a hole bored concentrically with thevfirst casing to a depth of say.a .thousand to The second hole is lined with, say, 12% casing from the surface of the ground to a depth-of'one thou-L Sometimes thecasing may be withdrawn -and saved but sometimes the well is a total loss -in all respects.

In accordance with the invention the use of casing is entirely avoided and the walls.

of the bore are sealed against both collapse and leaking by`producing a surface fusing of the material of the wall of the bore, such fusion and consequent closing up of the pores of the wall sometimes reaching several feet from suchwalls laterally into the earth. Such fusing `and sealing of the Walls is caused by the application of heat which may be accomplished by electrically heating the vwalls by the employmentof an intensity of heat sufficient for the purpose.

The invention not only lavoids the exr.

pense of metallic' casing for the bore but also avoids the expense` of installing such casing' and the costs due tothe frequent failure of the well4 to produce. The invention of course. does not insure a productive y well, but several wells may be sunk at a' cost no greater than that of sinking a single well in accordance with the commonpractice.

The invention will be best understood not a d ry Well.

' into the bore -stood that the formation indicated in the this specification, with the understanding, however, that the invention -is not confined to any strict conformity with the showing in the drawing, but may be changed and modified so. long as such changes and modifica-` tions mark no material departurev from the salient features of the invention as expressed in the appended claims.

The drawing is a more orless schematicV representation of a deep oil well formed in accordance with the invention.

In practising the invention there is first correspondingly deeper.

After the cellar 1 has `ibieen formed andl the casing section 3 has been set a bore-5 is carried down from the bottom of the casing 3 through the underlying strata, usually consisting of water-bearing sand stone 6, caving shale 7, cap rockv 8 and gas and oilbea-ring sand stone 9 and 10, respectively, when the well. is an oil producing well and The shale stratum 7 is by' far the most extensive one and the arrangement of v'strata is, substantially, that of the'lexas oil ields. Usually oil is struck at from three to four thousand feet and, customarily, such'wells are cased in the manner'already stated to prevent the entrance of Water from the strata 6 and the'caving of the shale 7, which is' of an unstablev nature, into the bore. In accordance Witli'the invention air ,under pressure is introduced into the bore.5 as it is formed and sufficient air pressure is employed to hold back the water which may occur i'n the strata 6 from entrance intoV the bore. It is to be' underdrawing is but a general representation, since the strata may be multiplied and, to an extent, repeated, before the oil-bearing sand stone is reached,`but the drawing in- 'I so 7 the valve'll is v Xin any desirable manner, usually dicates in general the formation Vwhich .is encountered in the'TeXas`oil fields and which.

also occursin other oil fields.

'In order-to maintain a desirable air pressure Within the bore while being formed the casing 3 is provided at a suitable heightwith a valve 11 having a controlling rod 12 reaching to the surface of the ground, or to 'other approriate point where it may be manipulate ntering the casing 3 below ay pipe 13 supplied with air by a force pump v14: driven by electricity so as to avoid the necesslty of emr under pressure `plc'r'ying. steam engines, boilers, etc., in the neighborhood of the Well.

The `method of drilling oil Wells without casing them before described herein forms the subject matter ofan application for a method of drillin wells filed by me on March 31, 1920, `erial No. 370,226. rl`he present application has more particular reference to a method of sealing `or lining the walls of the bore to avoid the necessity of using metallic casing in the customary man- For this purpose there is provided'an electric heater 15 of suitable -capacity to bring vabout the melting and coalescen'c'e of the material of the walls of the bore producing thereby a sort of slag or glass pene-l trating the Walls toa sufiicient extent to produce a lining 16, impervious to moisture and strong enough to prevent thecollapsing or caving of the shale. The electric heater may be made in accordance with the usual practice of forming electric heaters capable of producing a high degree of heat like that produced in the electric f nrnace, andthe heater 15 is so constructed that it-ma'y be moved lengthwise of thebore inclose relation to the walls thereof, and, in the con:-

fined space of the'bore,'causing the requisite high temperature. Experience has shown that thematerial encounteredin boring the Well will, under the heat-employed, melt toI consistency and so cement `lthe a lowin shale wal s and melt the water-bearing sand stone into a glass-like slag which will naturally run down the walls of the waterbearing sand stone, drying them out, and filllng up the pores of the sand stone so that the flow of the water into the -Well bore is effectively prevented. The' slag-like formation in the s and stone layer 6 is indicated at 16 and the melted and coalesced shaleis in dicated at 17. It is unnecessary to lcontinue the heating below the casing shale as the cap rock strata 8 is impervious to Water, both` rock' formations -4 and 8 beingn formed of h me stone.

Preliminary to the heating operation, whereby. the ,Waterbearing and unstable Walls of the bore arerendered impervious to Water and arestabilized, the bore is made down'to the cap rock overlyingl the gas and oil bearing sand stone with the Water held by and caving prevented by suitable lair pressure established in the bore. After the l i bore is produced the drilling tools are withdrawn with .the holding pressure still main- .tamed and the heater 151s introduced into the bore and moved'along the latter lat a rate and ina manner to cause the 4sealing of the water-bearing sand 'stone and the coalescence of the caving shale, thereby producing a permanentlining from-materials already present in the walls of the bore and at a cost far less than the usual casing employed. v

The heater 15 s furnished with a heating strata of the formatioh throu h which the through the .casing 3, the cable 18 being properly sealed where passing through a cap' 19 at,the top of the casing 3i and which cap may be above ground. In the -drawin lthere is' indicated ai transformer 20 wit which the cable 18 is connected, the transformer being of the character to furnish the heating current. No attempt isl made to 4show inv the drawing the type -of transformer, or transformers, which maybe employed, Vsince these features are all familiar to electrical engineers. After the walls of against the admission of water and` so coalesced that caving can no longer occur, the air pressure may be cut off andthe heater withdrawn and the wellvput into service in the usual manner.

The invention eliminates to a large extent' the necessity of the use of expensive casing and the various troubles which occur with suchuse, -for oftentimes inlintrodicing the casing various troubles occur resulting' in the totalloss ofthe casing and of the well for the collapsing of the casing and the impossibility of withdrawing casing causes the abandonment of wells which have not yet reached the oil bearing strata, which abandonment would not be necessary whereI uthe well is formed and lined in the manner hereinbefore described. 1

The heating outfit may be used repeatedly and so entails little or no cost after the ini` tial installation7 except 'for current, and

while such cost .maybe considerable it is not 'Y to be compared to the cost of casing and the sinking of such casing with attendant losses,

sometimes resulting in the total loss of the well. f s v l y While the transformer 2O is shown as located above ground itv isunderstood that the transformer may be and preferably i should be located in the bore as near as prac-v ticableto the heater,"since the heating current is a very low voltage current of great amperage requiring heavy conductors.

What is ,claimed is: v i. 1. The method of sealing the wallslof oil wells which consists in electrically 'heating the walls of the water-bearing and caving 'current through a cable 18 extending r the bore are sealedi l well is bored, with the heat o an intensity to cause the melting and coalescing of the material of the walls.V

2. The method of sealing the 'walls of oil.

ing the wallsto internal pressure holding the v material against flow and collapse of the walls u ntil the melted material has cooled and seti A c 3. The method of sealing the walls of oil wells 'which consists in subjecting the walls to the effect of electrically produced heat in close heat transferring relation to said walls for a time and with the heat of an intensity toproduce the melting of the material of the walls and its flow and coalescence into the form of a linin thereby sealing the -walls against the low of liquids therethrough andthe collapse of the walls when they have cooled to the-normal temperature ofthe well.

4:. The methodrof sealing the walls of 'oil wells traversing Water bearing and collapsible or caving strata which consists in establishing, in operative relation to the portions of thewalls Vto be sealed, electrical heat conditionsto dry out and melt the Water bearing f material to self-coalescingl softness and to melt the caving material to coalescing softness whereby when the walls cool there is `produced a slag-like -lining yimpervious to liquids and sealed or anchored against -cav- The method of sealing the walls of oil wells traversing water-bearingand unstable or ycaving strata, which consists in electrically heating the walls While subjected to Ainternal pressure, to a degree causing the sdftening and melting of the material ofthe walls to produce coalescing thereof while held by the internal pressure and continuing the internal pressure after the heat is cut-off until the material of the walls has set and thereby formed intoK a natural casing.

In testimony that I claim the foregoing 'as my own I have hereto aixed Vmy signature. WILLIAM E. NOLAN.v 

